First things first

In order to rewrite the VM of Net Core, I have to get the VM source code to compile under Clang. Then, using Piggy, I can start to convert the C++ code to C#. The first block of code I plan to work on is the PE file reader.

While I can build Coreclr on Windows through a VS Developer Command Window, Cmake fails to generate build files within a Mingw Bash shell. In fact, I had no idea whether Clang was used even on Linux, because is opaque: there are no options to the script to display compilations (at least not that I can see). Years ago, make had such an option, but it seems to have changed. It is now done via “make VERBOSE=1”.

But, using the Ubuntu WSL c:/Windows/System32/bash.exe, I was able to get the build working, and examine the compile commands. Note it’s important to install the various prerequisites, otherwise Coreclr won’t build.

The question is very simple: what compiler options do I need for Clang++ in order to compile VM/*.cpp using Piggy? After a bit of work, a typical compile is this:

pushd /mnt/c/Users/Kenne/Documents/coreclr/bin/obj/Linux.x64.Debug/src/vm/wks; /usr/bin/clang++ -DAMD64 -DBIT64=1 -DBUILDENV_CHECKED=1 -DDBG_TARGET_64BIT=1 -DDBG_TARGET_AMD64=1 -DDBG_TARGET_AMD64_UNIX -DDBG_TARGET_WIN64=1 -DDEBUG -DDEBUGGING_SUPPORTED -DDISABLE_CONTRACTS -DFEATURE_ARRAYSTUB_AS_IL -DFEATURE_CODE_VERSIONING -DFEATURE_COLLECTIBLE_TYPES -DFEATURE_CORECLR -DFEATURE_CORESYSTEM -DFEATURE_CORRUPTING_EXCEPTIONS -DFEATURE_DBGIPC_TRANSPORT_DI -DFEATURE_DBGIPC_TRANSPORT_VM -DFEATURE_DEFAULT_INTERFACES=1 -DFEATURE_EVENTSOURCE_XPLAT=1 -DFEATURE_EVENT_TRACE=1 -DFEATURE_HIJACK -DFEATURE_ICASTABLE -DFEATURE_ISYM_READER -DFEATURE_JUMPSTAMP -DFEATURE_LEGACYNETCF_DBG_HOST_CONTROL -DFEATURE_MANAGED_ETW -DFEATURE_MANAGED_ETW_CHANNELS -DFEATURE_MANUALLY_MANAGED_CARD_BUNDLES -DFEATURE_MULTICASTSTUB_AS_IL -DFEATURE_MULTICOREJIT -DFEATURE_MULTIREG_RETURN -DFEATURE_PAL -DFEATURE_PAL_ANSI -DFEATURE_PAL_SXS -DFEATURE_PERFMAP -DFEATURE_PERFTRACING=1 -DFEATURE_PREJIT -DFEATURE_READYTORUN -DFEATURE_REJIT -DFEATURE_STANDALONE_GC -DFEATURE_STANDALONE_SN -DFEATURE_STRONGNAME_DELAY_SIGNING_ALLOWED -DFEATURE_STRONGNAME_MIGRATION -DFEATURE_STUBS_AS_IL -DFEATURE_SVR_GC -DFEATURE_SYMDIFF -DFEATURE_TIERED_COMPILATION -DFEATURE_USE_ASM_GC_WRITE_BARRIERS -DFEATURE_USE_SOFTWARE_WRITE_WATCH_FOR_GC_HEAP -DFEATURE_WINDOWSPHONE -DFEATURE_WINMD_RESILIENT -DLINUX64 -DPLATFORM_UNIX=1 -DPROFILING_SUPPORTED -DUNICODE -DUNIX_AMD64_ABI -DUNIX_AMD64_ABI_ITF -DURTBLDENV_FRIENDLY=Checked -DWRITE_BARRIER_CHECK=1 -D_AMD64_ -D_BLD_CLR -D_DBG -D_DEBUG -D_SECURE_SCL=0 -D_TARGET_64BIT_=1 -D_TARGET_AMD64_=1 -D_UNICODE -D_WIN64 -I/mnt/c/Users/Kenne/Documents/coreclr/bin/obj/Linux.x64.Debug/src/vm/wks -I/mnt/c/Users/Kenne/Documents/coreclr/src/vm/wks -I/mnt/c/Users/Kenne/Documents/coreclr/src/vm -I/mnt/c/Users/Kenne/Documents/coreclr/src/pal/prebuilt/inc -I/mnt/c/Users/Kenne/Documents/coreclr/bin/obj -I/mnt/c/Users/Kenne/Documents/coreclr/src/pal/inc -I/mnt/c/Users/Kenne/Documents/coreclr/src/pal/inc/rt -I/mnt/c/Users/Kenne/Documents/coreclr/src/pal/src/safecrt -I/mnt/c/Users/Kenne/Documents/coreclr/src/inc -I/mnt/c/Users/Kenne/Documents/coreclr/src/strongname/inc -I/mnt/c/Users/Kenne/Documents/coreclr/src/inc/winrt -I/mnt/c/Users/Kenne/Documents/coreclr/src/debug/inc -I/mnt/c/Users/Kenne/Documents/coreclr/src/debug/inc/amd64 -I/mnt/c/Users/Kenne/Documents/coreclr/src/debug/inc/dump -I/mnt/c/Users/Kenne/Documents/coreclr/src/md/inc -I/mnt/c/Users/Kenne/Documents/coreclr/src/classlibnative/bcltype -I/mnt/c/Users/Kenne/Documents/coreclr/src/classlibnative/cryptography -I/mnt/c/Users/Kenne/Documents/coreclr/src/classlibnative/inc -I/mnt/c/Users/Kenne/Documents/coreclr/bin/obj/Linux.x64.Debug/src/inc -I/mnt/c/Users/Kenne/Documents/coreclr/src/pal/inc/rt/cpp -I/mnt/c/Users/Kenne/Documents/coreclr/src/nativeresources -I/mnt/c/Users/Kenne/Documents/coreclr/src/vm/amd64 -Wall -Wno-null-conversion -std=c++11 -g -O0 -fno-omit-frame-pointer -fms-extensions -fwrapv -fstack-protector-strong -ferror-limit=4096 -Werror -Wno-unused-private-field -Wno-unused-variable -Wno-microsoft -Wno-tautological-compare -Wno-constant-logical-operand -Wno-pragma-pack -Wno-unknown-warning-option -Wno-invalid-offsetof -Wno-incompatible-ms-struct -fsigned-char -nostdinc -fPIC -o CMakeFiles/cee_wks.dir/__/peimage.cpp.o -c /mnt/c/Users/Kenne/Documents/coreclr/src/vm/peimage.cpp; popd

This long, rambling command contains a wealth of information necessary to use Clang. With this in hand, I can now try to use Piggy.

Unfortunately, Clang of the code on Windows doesn’t work well. It seems easier to get Piggy to work under Linux than for Coreclr to compile with Clang on Windows.

Note, there is going to be a lot of work needed to develop the patterns required to do the conversion. Piggy itself will need to be extended to allow both Listener- and Visitor-patterns because the Visitor-pattern is insufficient.


2 thoughts on “First things first

    1. I’m working on Campy, but the runtime is the issue: the runtime (either Net Core or Framework or Mono) contains methods written in C as an optimization. C code isn’t compiled into NET CIL, and can’t be translated to PTX using the usual LLVM code generator. Currently, each method must then be rewritten in C# or written in in CUDA, hence the reason why I say Campy has a “substituting runtime”. But, either way, it’s a laborious process to rewrite all these methods. What I’m interested in is a more automated way to translate the code into C#. That’s what I’ve been working on for the last year, and will take some time to get it to work.

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